These data were used for an analysis of Steller sea lion pup health and condition by Lander et al. (2013). Serum chemistry and hematological values were measured by analysis of blood samples taken from 1,231 Steller sea lion pups (<2 months old). Pups were captured by hand or with hoop nets at 37 rookeries across their Alaskan range during mid-June to early July. Blood samples were collected from the caudal gluteal vein into EDTA and serum separator tubes. For details on analytical methodology, see Lander et al. (2013).